RESUMO
OBJECTIVES: To test the tolerance and safety of an alveolar recruitment manoeuvre performed in the immediate postoperative period of corrective open heart surgery in children with congenital heart disease associated with excessive pulmonary blood flow and pulmonary arterial hypertension due to left-to-right shunt. METHODS: Ten infants aged 1-24 months with congenital heart disease associated with excessive pulmonary blood flow and pulmonary artery hypertension (mean pulmonary artery pressure ≥ 25 mmHg) were evaluated. The alveolar recruitment manoeuvre was performed in the operating theatre right after skin closure, and consisted of three successive stages of 30 s each, intercalated by a 1-min interval of baseline ventilation. Positive end-expiratory pressure was set to 10 cmH2O in the first stage and to 15 cmH2O in the two last ones, while the peak inspiratory pressure was kept at to 30 cmH2O in the first stage and at 35 cmH2O in the latter ones. Haemodynamic and respiratory variables were recorded. RESULTS: There was a slight but significant increase in mean pulmonary artery pressure from baseline to Stage 3 (P = 0.0009), as well as between Stages 1 and 2 (P = 0.0001), and 1 and 3 (P = 0.001), with no significant difference between Stages 2 and 3 (P = 0.06). Upon completion of the third stage, there were significant increases in arterial haemoglobin saturation as measured by pulse oximetry (P = 0.0009), arterial blood partial pressure of oxygen (P = 0.04), venous blood oxygen saturation of haemoglobin (P = 0.03) and arterial oxygen partial pressure over inspired oxygen fraction ratio (P = 0.04). A significant reduction in arterial blood partial pressure of carbon dioxide (P = 0.01) and in end tidal carbon dioxide also occurred (P = 0.009). The manoeuvre was well tolerated and besides a slight and transitory elevation in mean pulmonary artery, no other adverse haemodynamic or ventilatory effect was elicited. CONCLUSIONS: The alveolar recruitment manoeuvre seemed to be safe and well tolerated immediately after open heart surgery in infants liable to pulmonary hypertensive crises.
Assuntos
Pressão Arterial , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Cardiopatias Congênitas/cirurgia , Hipertensão Pulmonar/etiologia , Respiração com Pressão Positiva/métodos , Alvéolos Pulmonares/fisiopatologia , Artéria Pulmonar/fisiopatologia , Circulação Pulmonar , Dióxido de Carbono/sangue , Pré-Escolar , Feminino , Cardiopatias Congênitas/complicações , Cardiopatias Congênitas/fisiopatologia , Humanos , Hipertensão Pulmonar/sangue , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/fisiopatologia , Lactente , Masculino , Oxigênio/sangue , Pressão Parcial , Projetos Piloto , Respiração com Pressão Positiva/efeitos adversos , Estudos Prospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
JUSTIFICATIVA E OBJETIVOS: A patogênese da síndrome do desconforto respiratório agudo (SDRA) tem sido explicada pela presença de uma agressão direta (SDRA pulmonar) e/ou indireta (SDRA extrapulmonar) ao parênquima pulmonar. Evidências indicam que a fisiopatologia da doença pode diferir com o tipo de lesão. O objetivo deste estudo foi apresentar breve revisão das diferenças entre a SDRA pulmonar e a SDRA extrapulmonar e discutir as interações entre os aspectos morfofuncionais e a resposta aos diferentes tratamentos. CONTEÚDO: Esta revisão bibliográfica baseou-se em uma pesquisa sistemática de artigos experimentais e clínicos sobre SDRA incluídos nas bases de dados MedLine e SciElo nos últimos 20 anos. Muitos pesquisadores concordam, com base em estudos experimentais, que a SDRA pulmonar e a SDRA extrapulmonar não são idênticas no que diz respeito aos aspectos morfofuncionais, a resposta à pressão positiva ao final da expiração (PEEP), manobra de recrutamento alveolar, posição prona e outras terapias farmacológicas. Entretanto, os estudos clínicos têm descrito resultados contraditórios, os quais podem ser atribuídos à dificuldade de se classificar a SDRA em uma ou outra etiologia, e de se precisar o início, a fase e a gravidade da SDRA nos pacientes. CONCLUSÕES: Pacientes com SDRA de etiologias distintas perduram sendo considerados como pertencendo a uma mesma síndrome e, assim, são tratados da mesma forma. Logo, é fundamental entender as diferenças fisiopatológicas entre a SDRA pulmonar e extrapulmonar para que a terapia seja mais bem direcionada.
BACKGROUND AND OBJECTIVES: The pathogenesis of acute respiratory distress syndrome (ARDS) has been described by the presence of direct (pulmonary) and/or indirect (extrapulmonary) insult to the lung parenchyma. Evidence indicates that the pathophysiology of ARDS may differ according to the type of primary insult. This article presents a brief overview of differences between pulmonary and extrapulmonary ARDS, and discusses the interactions between morpho-functional aspects and response to differents therapies, both in experimental and clinical studies. CONTENTS: This systematic review included clinical and experimental ARDS studies found in MedLine and SciElo databases in the last 20 years. Many researchers acknowledge that experimental pulmonary and extrapulmonary ARDS are not identical with regard to morpho-functional aspects, the response to positive end-expiratory pressure (PEEP), recruitment manoeuvre, prone position and other adjunctive therapies. However, contradictory results have been reported in different clinical studies, which could be attributed to the difficulty of classifying ARDS in one or the other category, and to the assurance regarding the onset, phase and severity of ARDS in all patients. CONCLUSIONS: Heterogeneous ARDS patients are still considered as belonging to one syndrome, and are therefore treated in a similar manner. Thus, it is important to understand the pathophysiology of pulmonary and extrapulmonary ARDS in an attempt to better treat these patients.